A well-known apparatus for reducing sound is based on a single static loudspeaker arrangement which is not adapted to be regulated depending on the occurring sound to be reduced. Rather, that apparatus generates a broad-band counter-sound which cannot be controlled. Such designs having broad-band counter-sound devices make it possible to reduce noise by about 6 dB but have poor efficiency since they are not self-regulating. Moreover, such devices are heavy and often have relatively large loudspeaker arrangements. By having such feature they are not suitable for use in all fields of application, such as, for example, for a use in an aircraft. Such well-known methods for generating counter-sound for noise reduction are based on individual components which are not attuned to the frequency to be generated but to broad-band transmission behaviour. Hence, these methods do not provide reasonable efficiency for a narrow-band field of application such as, for example, for active reduction of a propeller noise, wherefore it is necessary to use amplifiers with considerable electrical input. However, such amplifiers are quite heavy and thus disadvantageous in mobile applications as, for example, in the field of aviation.